About a dozen people of faith from congregations across Indianapolis marched through downtown to deliver a message: Indianapolis Power & Light's latest rate hike request is immoral.

The group, whose members were also involved with Indiana environmental organizations, stopped to pray in front of IPL's headquarters before hand delivering a letter to the Office of Utility Consumer Counselor. The state agency represents ratepayer interests in state and federal utility cases.

In December, IPL filed with the Indiana Utility Regulatory Commission for authorization to raise rates and charges for its electric service. The increase would provide them with $96 million in additional operating revenue.

The letter, coordinated by Hoosier Interfaith Power and Light, quotes a speech by Pope Francis, who said in a 2013 speech, "let us be 'protectors' of creation, protectors of God’s plan inscribed in nature, protectors of one another and of the environment."

Copies of the letter were also sent to the Indianapolis City-County Council and Mayor Joe Hogsett.

"I think our love of humanity, irrespective of profit, should motivate us to make good decisions," said Pastor Heath Jones, who heads Northwood Christian Church in the Meridian Kessler neighborhood. He said that higher bills put pressure on households and communities, which then become unstable environments for children.

"Putting the profits over healthy homes and healthy communities and a healthy city, to do that is immoral, and I speak that way as a minister of the gospel," he added.

Using the fixed monthly charge and kilowatt hour usage charge, an IndyStar calculation found that residential customers could see an increase on their monthly bill of as much as $20. IPL disputes that estimate, claiming that the increase would be closer to $11.50 per month. Company representatives attributed the difference in the estimates to unpredictable "tracker" charges that they said would likely be lower in the future compared to what they are now.

What is clear, according to filings with the IURC, is that IPL would no longer be the lowest cost utility in Indiana, jumping from fifth to third place among Indiana's five investor owned utilities.

H-IPL's letter, which has been endorsed by nearly five dozen clergy and people of faith, also calls for the retirement of IPL's Petersburg Station, a coal-fired power plant in Pike County with a generating capacity of 1,720 megawatts.

"It is literally one of the worst power plants in the entire country, and our city should be embarrassed that it’s where our power comes from," said Mike Oles, an advocacy and community organizing consultant for H-IPL.

IPL serves around 490,000 retail customers in Central Indiana. Its current basic rates and charges have been in effect since May 2016. Since then, the company said it has spent more than $2 billion in additions, replacements and improvements to its electric utility properties, including work to convert the Harding Street Station in Indianapolis from coal to natural gas. The proposed increase would go towards additional capital improvements and operating expenses.

"IPL is providing a more balanced generation mix by building a natural gas plant that will generate cleaner, more reliable and efficient energy at a reasonable cost, by closing older outdated units and by converting certain coal-fired units to natural gas, among other infrastructure improvements," Dalton said in an emailed statement.

This is not the first time Hoosier Interfaith Power and Light and other faith and environmental groups have called for justice related to Indiana's energy issues.

In 2013, H-IPL joined the Sierra Club, the NAACP and Citizens Action Coalition in a billboard campaign calling for the closing of IPL's Harding Street coal plant. IPL announced in 2016 that it would not longer burn coal at the Harding Street station, and would instead convert the plant to natural gas. If approved, money from this most recent rate hike would go towards funding that conversion, according to documents filed with the IURC.

Emily Hopkins covers the environment for IndyStar. Contact them at (317) 444-6409 or emily.hopkins@indystar.com. Follow them on Twitter: @_thetextfiles.

Sarah Bowman contributed to this report.

IndyStar's environmental reporting project is made possible through the generous support of the nonprofit Nina Mason Pulliam Charitable Trust.